The present invention relates to a heat transport system for transporting heat from a heat generating portion to a cooling portion by circulating a working fluid which is changeable in phase. The heat transport system according to the present invention is especially useful in space where there is no gravity.
FIG. 5 and FIG. 6 are, for example, prior heat transport systems disclosed in Japanese Patent Publication No. 29196/1988.
This invention is an improvement of such prior heat transport systems. The construction and operation thereof will be explained hereinafter.
FIG. 5 shows a first operating mode of the prior heat transport system in which an on off valve 11 is closed and a three-way valve 7 is set to place an accumulator 3 in fluid communication with a liquid pipe 13.
Also, FIG. 6 shows a second operating mode of the prior heat transport system in which the on-off valve 11 is opened and the three-way valve 7 is set to place the accumulator 3 in fluid communication with a communicating pipe 4.
In these figures, reference numeral 1 is an evaporator, 2 is a condenser in which working fluid in vapor phase is condensed and liquefied due to heat radiation, 3 is an accumulator, 4 is a communicating pipe which communicates the vapor phase 5 in the evaporator 1 with the vapor phase 6 in the accumulator 3 to balance the inside pressure of the evaporator 1 with that of the accumulator 3. Reference numeral 7 designates a three-way valve having three ports toward the communicating pipe 4, a liquid pipe 13 and the accumulator 3 respectively. Reference numeral 8 designates a liquid returning pipe which communicates the liquid phase 9 in the accumulator 3 with the liquid phase 10 in the evaporator 1. Reference numeral 11 designates an on-off valve positioned in the middle of the liquid returning pipe 8. Reference number 12 designates an vapor pipe which communicates the evaporator 1 with the condenser 2. Reference numeral 13 designates a liquid pipe through which the liquefied working fluid flows from the condenser 2 to the accumulator 3. Reference numeral 14 designates a heat generator such as an electronic apparatus or the like which is mounted on the evaporator 1. Reference numeral 15 designates a radiator which is provided in contact with the condenser 2.
The vapor pipe 12, the liquid pipe 13 and the liquid returning pipe 8 form a closed loop with the evaporator 1, the condenser 2 and the accumulator 3. The condensed working liquid 16 such as freon, alcohol, ammonia or the like flows through the closed loop. The volume of the working liquid 16 may be selected in accordance with the desired operating conditions of the heat transport system and the other factors, as is well-known in the prior art.
The first operating mode shown in FIG. 5 and the second operating mode shown in FIG. 6 are explained hereinafter.
In the first operating mode, the on off valve 11 is closed and the three way valve 7 operates to place the accumulator 3 in communication with the liquid pipe 13. The working liquid 16 in the evaporator 1 is vaporized due to heat generated by a heat generator 14, such as an electronic heating apparatus.
The vapor from the evaporator 1 arrives at the condenser 2 through the vapor pipe 12, as shown by dashed arrow lines in FIG. 5, and is cooled and then liquefied in the condenser 2 due to the extraction of heat from the vapor. The liquefied fluid is pushed out from the condenser 2 by vapor pressure flowing in from the evaporator 1, and flows into the accumulator 3 through the liquid pipe 13, as is shown by solid arrow lines in FIG. 5. The liquid in the evaporator 1 is used for the above-mentioned heat transportation medium.
In the second operating mode as shown in FIG. 6, the on-off valve 11 is opened and the three-way valve 7 is switched to communicate the accumulator 3 with the communicating pipe 4. That is, in this second operating mode, vapor in the evaporator 1 flows into the accumulator 3 through the communicating pipe 4, as shown by a dashed arrow line. And the liquid 9 in the accumulator 3 returns to the evaporator 1 through the liquid returning pipe 8 and the on-off valve 11, as is shown by solid arrow lines in FIG. 6. In the second operating mode, the liquid moves according to the height difference between the liquid 9 in the accumulator 3 and the liquid 10 in the evaporator 1, i.e. on the basis of the gravity in the environment of use.
In these prior transport systems, the first operating mode shown in FIG. 5 and the second operating mode shown in FIG. 6 are alternatively switched at an appropriate time interval using the three-way valve 7 and the on-off valve 11.
As stated above, during the continuous switching between the first operating mode and the second operating mode, the heat generated in the heat generator 14 is transported from the evaporator 1 to the condenser 2 by working liquid 16 which is cooled at the condenser.
However, a disadvantage of the above-mentioned prior heat transport system is that it cannot be used in space where there is little or no gravity, because gravity is relied upon for returning the liquid in the accumulator 3 to the evaporator 1 in the second operating mode as above-mentioned.